The purpose of this application is to bring about a change in the institutional sponsorship of an already approved grant. Since the work will be carried out in the same geographical location and under identical circumstances, there will be no effect on the objectives or performance of the research project. Glycoproteins are widely distributed in animal tissues and represent one of the major groups of conjugated proteins. Their importance in many physiological and pathological processes is becoming increasingly apparent. It is planned to continue a study of the biosynthetic processes involved in the assembly of the carbohydrate units of glycoproteins and their attachment to the peptide portion. An understanding of the assembly of the carbohydrate portion is important, as it represents the final step in the synthesis of these proteins before they are ready to assume their biological functions. Emphasis will be placed on those glycoproteins for which detailed structural information has already been obtained in this laboratory, including fetuin and thyroglobulin, with their asparagine-linked heteropolysaccharide units and collagens and basement membranes, with their distinctive hydroxylysine-linked carbohydrate. Glycosyltransferases responsible for the assembly of the carbohydrate units and for the attachment of the most internal sugar to a specific amino acid in the peptide chain will be isolated and characterized. The specificity of these enzymes, in regard to acceptor and sugar nucleotide, is thought to determine the structural patterns found in glycoproteins. In vivo radioisotope studies will be conducted in order to elucidate the intra- or extracellular site of the carbohydrate attachment during the synthesis of the renal glomerular basement membrane and to obtain information in regard to precursors and rate of turnover. Of particular interest is the influence which high levels of blood glucose may have upon the synthesis of the capillary basement membranes and thereby on the pathogenesis of the diabetic microangiopathy.